26 Emergency lighting
Although the performance of LED emergency lighting has increased over time, this doesn’t mean designers should just focus on delivering a higher lumen output
any areas of risk and identify the types of lampheads and optics that are best suited for each space (for example high bay, corridor and so on). In this respect, it can be very useful to carry out a risk assessment to help in determining the requirements for compliance. This may well involve working with the architect and end-user to understand the use of the space, as this will help to determine how best the scheme should be designed and maintained throughout the life of the installation. It may also be useful to model the space in which the emergency lighting is to be installed. For instance, the lighting designer may find initial estimations based on generic spacing tables are in excess of the emergency light levels required. With careful positioning and use of appropriate lamphead/optic arrangements, it may then be feasible to further optimise the spacings to reduce costs whilst ensuring the scheme is safe, compliant and designed to the application. By focusing on application requirements, other factors, such as the way the emergency lighting scheme is powered, maintained and operated, play a much more vital role. This will ultimately result in a system being far more beneficial than if the lumen output was the sole focus. UNDERSTAND THE POTENTIAL Emergency lighting now offers a whole range of options, which have been developed with engineers and end users in mind. There are number of cases where emergency lighting has been neglected
Lighting Journal April 2016
or the maintenance requirements have not been fully understood by the individual who is responsible. Implementing automatic test systems and intuitive emergency control platforms help engineers and end users to ensure the entire emergency lighting system is operating as intended and is compliant. Emergency lighting controls that notify users of potential issues or problems that need further investigation all aid in demystifying the processes required to ensure good practice and maintain a simple approach to monitoring a small or large scale scheme. As lighting has evolved to become part of the ‘Internet of Things’, emergency lighting doesn’t have to be seen as an entity that works against this switch to more intelligent, smart building platforms. There is now the option to power and communicate with emergency lighting via category cable alone. This is great for adopters of the ‘Power over Ethernet’ revolution, as it means both the general lighting and emergency lighting can operate on the same type of cabling. This is turn helps to prevent costly isolation and additional terminations from trying to run a line voltage to ceiling luminaires. Understanding the range of options available and selecting emergency lighting systems that work in harmony with general lighting will help to instil confidence in those that are tasked with maintenance and operation, resulting in a system which is monitored and checked regularly and properly. However, the way emergency lighting is powered and monitored is not the
only consideration. Emergency lighting products are now available with a range of battery options, including lithium-ion. Each battery will have its own benefits and drawbacks, putting the emphasis on understanding the requirements of the project. The temperature and environment the emergency lighting will be housed in has an impact on how the battery will perform, and has implications on lifespan. Most batteries can charge and operate consistently in a range of temperatures, but technologies such as lithium-ion may need additional precautions to prevent undesirable situations, such as thermal runaway. It may seem daunting when considering which products are the best for the scheme, but with careful planning and understanding of existing systems or protocols, selecting the right product becomes straightforward. The main point is to be aware emergency lighting has evolved, just the same as general lighting. By focusing on the lumen output alone, this excludes any opportunities to reduce power consumption and save money on the total cost of the scheme. Ultimately, just like any lighting scheme, emergency lighting needs to work as an integrated whole, in harmony with both the needs of the building and its occupants to create a safe and compliant system that is both future proof and fit for purpose. Byline: Joseph Handley is design engineer at Mackwell Electronics
POINTS TO ADDRESS In designing an emergency lighting scheme to make best use of the technology available, it is important to consider the following points: • Understand the application • Know how the space will be used • Rather than focusing on lumens, look at the optics used and spacing table information • Model the space and see how the luminaires will perform • Ensure the scheme is safe and compliant by following local standards and regulations • Look at various technology options and battery variants available to see if these bring any benefits to the project • When working on a retrofit project, find out what the pain points were with any existing systems and try to avoid making similar mistakes • Seek advice from professionals when in doubt